1. Field of the Invention
The invention relates to ultrasonic transducers.
2. Description of Prior Art
The invention relates more particularly to such transducers for use in bonding tools for connecting semiconductors to printed circuit boards for example. The bonding tools are used to apply pressure and ultrasonic energy simultaneously to miniature components for making electrical connections between them. The materials used in the driver of the ultrasonic transducers are piezoelectric ceramics. In different stages in the bonding process, there are parameters that must be monitored including the amplitude of the ultrasonic burst and its duration (bonding time). An optimized range of these bonding parameters which ensures the required bond quality is usually determined for each type of bonding machine. At present, all the bond parameter monitoring sensors are installed separated from the piezoelectric driver or may be attached to the ultrasonic concentrator.